1. Field of the Invention
The present invention relates to a figure selection method, a figure selection device, and a storage medium storing a figure selection program when an arbitrary figure is selected for editing to make correction, transfer, copy, cancellation, grouping, conversion into 2D(two dimension)/3D(three dimension), and so on, in a CAD system or the like.
2. Description of the Related Art
A selection operation of a figure to be edited is frequently repeated for editing to make correction, transfer, copy, cancellation, grouping, conversion into 2D(two dimension)/3D(three dimension) and and so on, in a CAD system or the like.
A figure is generally represented by a point, a line, a plane, a solid, or a collection thereof or a part thereof (edge or the like). A figure element is a basic unit to form a figure, and it is broadly represented by a point, a line, a plane, a solid, or a collection thereof or a part thereof (edge or the like). Narrowly speaking, however, a figure element is represented by a line, but in the present specification, it is represented by linear data including a straight line, a curved line, a circle, an arc, a spline curved line and the like.
FIG. 1 is a diagram explaining a pick-method of the first prior art.
In FIG. 1, in order to select a figure 5100 formed by figure elements 5101, 5102, 5103, 5104, 5105, 5106, 5107 and 5108 using a pick-method, an arrow-shaped pointer 5110 is displayed on a display using an input unit such as a mouse or the like, and the mouse is clicked placing a head of the pointer 5110 on at least six figure elements 5101, 5102, 5103, 5104, 5106, and 5108, thereby selecting the desired figure 5100.
FIG. 2 is a diagram explaining a chain retrieval method of the second prior art. In FIG. 2, in order to select a figure 5200 formed by figure elements 5201 to 5104 using a chain retrieval method, an arrow-shaped pointer 5210 is displayed on a display using an input unit such as a mouse or the like similarly to the pick-method, and the mouse is clicked placing a head of the pointer 5210 on the figure element 5201 which is one of the figure elements forming the figure 5200 to be selected. Thus, the system automatically selects figure elements 5202, 5203, and 5204 which uniformally follow the figure element 5201, thereby selecting the desired figure 5200.
FIG. 3 is a diagram explaining a maximum/minimum closed-loop retrieval method of the third prior art.
In FIG. 3, an arrow-shaped pointer 5320 is displayed on a display using an input unit such as a mouse or the like, and the mouse is clicked placing a head of the pointer 5320 on a figure element 5301 which is one of the figure elements. Thus, in the maximum closed-loop retrieval method, the system retrieves a maximum closed-loop figure 5330 formed by figure elements 5301, 5302, 5303, 5304, 5305, 5306, 5307 and 5308. In the minimum closed-loop retrieval method, the system retrieves a minimum closed-loop figure 5340 formed by figure elements 5301, 5308, 5309, and 5310. Thus, desired figures 5330 and 5340 are selected.
As the forth prior art, there is a combination method of combining more than two methods of the above-mentioned pick-method, chain retrieval method, and maximum/minimum closed-loop retrieval method. When a desired figure is selected by the combination method, a desired figure is selected while selecting the respective methods depending on each mode in such a way that the pick-method is used in a pick-mode, the chain retrieval method is used in a chain retrieval mode, the maximum closed-loop retrieval method is used in a maximum closed-loop retrieval mode, and the minimum closed-loop retrieval method is used in a minimum closed-loop retrieval mode.
In the figure selection method described in each prior art, however, there have been the following problems.
In the case of the pick-method of the first prior art, operations should be performed many times for the selection of a desired figure. The mouse should be clicked on a figure element at least six times in order to select, for example, the figure 5100 shown in FIG. 1.
In the case of the chain retrieval method of the second prior art, the mouse is clicked on a figure element only one time, but only the figure formed by a group of figure elements following the mouse-clicked figure element can be selected. Therefore, the shape of a figure which can be selected is restricted. For example, the figure 5200 shown in FIG. 2 can be selected by clicking the figure element 5201 one time using a mouse. This is because the figure elements 5202, 5203 and 5204 are sequentially and uniformally determined following the figure element 5201. That is, only a figure in which another figure element is not connected with the connection part of two figure elements can be selected.
In the case of the maximum/minimum closed-loop retrieval method of the third prior art, a figure element is clicked only one time using a mouse similarly to the chain retrieval method. Further, a figure in which another figure element is connected with the connection part of two figure elements can be selected. The thus-selected figure is an outermost closed-loop figure, or an innermost closed-loop figure which contains a mouse-clicked figure element.
In the case of the combination method of the forth prior art, a figure can be selected making use of each advantage of the above-mentioned conventional figure selection methods described in the first to third prior arts. However, an additional operation such as the switching of each mode is required.
When the chain retrieval method or the maximum/minimum closed-loop retrieval method is used, figure elements to be connected cannot be retrieved by these methods in the following cases:
(1) Two figure elements to be connected are not connected in the case where errors are generated while a figure is being prepared or in the case where existing data stored in an old CAD system which uses precision data with single precision are transferred to a new CAD system which uses precision data with double precision; and(2) A cause-and-effect relationship exists between two figure elements even if they are not really connected as in the case where the figure elements are omitted or the figure elements are hidden lines.